Think of the saddest thing you can – the last puppy in the pet shop, or Takashi Shimura in that film by Kurosawa singing a song about blossom and the briefness of life (not the scene at the end where he sits on a playground swing as the snow falls, but earlier on where he brings the fun in the nightclub to a dead standstill as the tears well up in his eyes and everyone goes quiet). Not even that is as sad as a card saying: “Sorry I forgot your birthday.”

The footballer Yaya Touré is thinking of leaving Manchester City, his agent says, because his team-mates did not shake his hand and wish him Happy Birthday. “Card from City just arrived,” Touré tweeted. “Must have got lost in the post. Haha.”

The words “Sorry I forgot your birthday” are a synonym for “Sorry I don’t love you”. They contain an internal contradiction. If you were really sorry, you’d have remembered. Forgetting is the Dolorous Stroke which does far more than it intends: it lays the whole land waste and leaves the Fisher King (whoever he is) with a wound that cannot be healed.

When Auberon Waugh, aged 15, forgot his father Evelyn’s 52nd birthday, he retaliated by describing the glories of the day: “The silver band played continuously from dawn to dusk. Pontifical high mass was celebrated in Dursley church. In the evening an ox was roasted and eaten by Lady Tubbs.” Lady Tubbs was a local figure of fun. “Your brother Septimus,” Waugh concluded, “continues to give unusual pleasure.”

Yet, for one who was hurt by not being remembered, Evelyn Waugh behaved with scant empathy towards his eldest son. He refused to go to Auberon’s 20th birthday party, and his 21st, and had to be dragged from bed by his wife and forcibly dressed to attend his wedding. This fitted nicely into the bitter theme of Alexander Waugh’s brilliant book Fathers and Sons, about the visitation of violent hatred by one generation of male Waughs on the next. In such a pattern, birthdays merely illustrate Larkin’s theme in “This be the Verse”, his poem about what your mum and dad do to you: “Man hands on misery to man. / It deepens like a coastal shelf.”

Touré has not yet tweeted on this exact theme. As far as one can tell, for him Happy and Birthday go together like the most going-togethery things: horse and carriage, cheese and onion, Marks and Sparks. Quite how he got on during his three years at Barcelona, I don’t know. In those parts they celebrate saints’ day, not birthdays.

Luckily Yaya, a Muslim, is named after John the Baptist, who has two feast days every year: June 24 (nativity) and August 29 (beheading). So perhaps his Catalan team-mates beamingly brought him a cake full of bright candles twice a year, rather as our own dear Queen spends a quiet day at Windsor Castle with a few dozen close family on her real birthday and on her official birthday sees the Colour being Trooped and hears guns saluting her (41 times at Hyde Park, 62 at the Tower).

But if this month 31 tears silently coursed down Yaya’s forgotten birthday cheek, one for each footballing season of his life, blame must be placed on the British conspiracy that surrounds birthdays. The unspoken but iron-bound rule that governs them is that the birthday boy or girl must pretend it is a normal day. That, the folie à plusieurs dictates, is so that his family and friends can SURPRISE! him with a card, a cake, a sudden party.

Here is institutionalised deception on both sides. The thing so dearly wanted is tantalisingly hidden from sight, like supermarket cigarettes. With birthdays, as poor Yaya found out, the sentimental side of love is first hidden then revealed with a fanfare – a game of peep-bo with the heart. The disappointment if nothing happens is like ritualised burial alive. No wonder that then there’s no saying sorry.